chapter 12 notes - Notes transcribed Rna polymerase does...

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Notes transcribed Rna polymerase does not need a primer Rna product does not remain base paired to the template dna strand multiple rna polymerases can transcribe the same gene at the same time each following closely behind the other as the rna product releases dna reanneals shortly behind One in ten thousand or ten to the fourth amount of errors Eukaryotic have three rna polymerases Pol 1 – transcribes the large rna precursor gene Pol 2 – responsible for transcribing most genes Pol 3- transcribes t Rna genes some small nuclear rna genes and the 5s rrna gene Rna polymerase core enzyme is capable of synthesizing rna by itself Composed of two alpha units one beta and one beta prime and one omega Brings in two metal ions one is tightly boung and the second mg 2 plus ion is brought in with each new nucleotide in the addition cycle and released with the pyrophosphate Transcription initiation 1 st step closed complex dna is double stranded the enzyme is bound to one face of the helix 2 nd step closed complex undergoes a transition to the open complex in which the dna strands separate over a distance of 14 base pairs around the start site to form the transcription bubble first two ribonucleotides are brought into the active i=site in the open complex
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This note was uploaded on 04/07/2008 for the course BIO 325 taught by Professor Saxena during the Spring '08 term at University of Texas at Austin.

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chapter 12 notes - Notes transcribed Rna polymerase does...

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